The Foo Fighters are building a studio in Los Angeles to record their next RCA project, frontman Dave Grohl said. The group recorded its past several albums in Grohl’s basement in Virginia. “I think it’s going to be a two-record set,” he says. “It’s going to be 10 acoustic songs and then 10 tracks that are just koo-koo, really heavy.” He adds that the Foos already have a lot of acoustic material that the band has never recorded. The album will be the follow-up to 2002’s “One by One,” which debuted at No. 3 on The Billboard 200 and has sold 1.1 million copies in the United States, according to Nielsen SoundScan. It was named best rock album in February at the 46th Grammy Awards. For now, the lone date on the Foos’calendar is an Aug. 28 appearance at San Diego’s Street Scene Festival. As for his previously announced work on the upcoming Nine Inch Nails album, Grohl says NIN leader Trent Reznor called to ask if he would play, and they went into Sound City Studio in Van Nuys, Calif., the next day. “It sounds incredible,” Grohl says of the NIN material. “It is [Trent’s] first [studio] album in five years. I looked at him and said, ‘What have you been doing!’